func (ev *evaluator) eval(row sqlbase.EncDatumRow) (sqlbase.EncDatumRow, error) {
for i := range ev.exprs {
datum, err := (&ev.exprs[i]).eval(row)
if err != nil {
return nil, err
}
ev.tuple[i] = datum
}
outRow := ev.rowAlloc.AllocRow(len(ev.tuple))
if err := sqlbase.DTupleToEncDatumRow(outRow, ev.tuple); err != nil {
return nil, err
}
return outRow, nil
}
func (ag *aggregator) computeAggregates() error {
// Render the results.
tuple := make(parser.DTuple, 0, len(ag.funcs))
for bucket := range ag.buckets {
for _, f := range ag.funcs {
datum := f.get(bucket)
tuple = append(tuple, datum)
}
row := ag.rowAlloc.AllocRow(len(tuple))
err := sqlbase.DTupleToEncDatumRow(row, tuple)
if err != nil {
return err
}
if ok := ag.rows.PushRow(row); !ok {
return errors.Errorf("unable to add row %s", row)
}
tuple = tuple[:0]
}
return nil
}
func (ag *aggregator) computeAggregates() error {
// Queries like `SELECT MAX(n) FROM t` expect a row of NULLs if nothing was
// aggregated.
if len(ag.buckets) < 1 && len(ag.groupCols) == 0 {
ag.buckets[""] = struct{}{}
}
// Render the results.
tuple := make(parser.DTuple, 0, len(ag.funcs))
for bucket := range ag.buckets {
for _, f := range ag.funcs {
datum := f.get(bucket)
tuple = append(tuple, datum)
}
row := ag.rowAlloc.AllocRow(len(tuple))
sqlbase.DTupleToEncDatumRow(row, ag.outputTypes, tuple)
if ok := ag.rows.PushRow(row); !ok {
return errors.Errorf("unable to add row %s", row)
}
tuple = tuple[:0]
}
return nil
}
